A new mandarin citrus tree Citrus reticulata hybrid is described. The new variety named xe2x80x98Shanixe2x80x99 is desirable to the consumer because of the red-orange color and excellent flavor of its fruit and to the commercial grower because of its late-season fruit ripening.
The present invention relates to a new and distinct variety of mandarin citrus tree Citrus reticulata hybrid developed by inventors Pinchas Spiegel-Roy, Aliza Vardi, Avraham Elchanati and Ahuva Frydman-Shani in Bet Dagan, Israel from a controlled pollination cross between seed parent xe2x80x98Wilkingxe2x80x99 (unpatented) mandarin and pollen parent xe2x80x98Michalxe2x80x99 (unpatented).
Asexual reproduction by conventional bud grafting of the new variety at the Agriculture Research Organization Volcani Center in Bet Dagan, Israel, has shown that the new characteristics are stabilized and permanently fixed through successive propagation.
The objective in breeding the present new tree variety, assigned the denomination xe2x80x98Shanixe2x80x99, was to obtain a late ripening citrus mandarin with few or no seeds. In the spring of 1976, the seed parent xe2x80x98Wilkingxe2x80x99 (unpatented) mandarin (resulting from a cross of xe2x80x98Kingxe2x80x99xc3x97xe2x80x98Willowleafxe2x80x99 (Mediterranean) reported by Frost in Calif. Agr. Exp. Sta. Bull. 1935, pp.597-601), was crossed with pollen parent xe2x80x98Michalxe2x80x99, a cultivar of Israeli origin believed to be a natural hybrid between two Citrus reticulata xe2x80x98Blancoxe2x80x99 cultivars. The fruit was collected in November 1977. Seeds were extracted and germinated in January 1978. About 400 seedlings were grown from the germinated seeds. Each seedling was grafted onto Sour orange nucellar rootstock.
Field planting was established from container grown plants in the spring of 1979. The first fruits were observed in February, 1983 and again in 1984.
One of the 400 plants was designated 46/2. The fruits of this scion were observed to be fully ripe during February to mid March. The fruit was red-orange in color with few seeds and excellent flavor.
Bud wood was taken from 46/2 and top grafted in the spring of 1984 on 8 Troyer nucellar rootstock The grafted plants were planted a year later in the experimental grove of the Agricultural Research Organization, Bet Dagan, Israel. The first crop of these trees was obtained in 1987. The yield of the scion grafted onto Troyer rootstock was good. The fruit was fully ripe the last week in February. The color of the fruit when fully ripe was orange-red, and the fruit was quite easy to peel. The fruit had a pleasant flavor and excellent aroma. The juice had a sugar concentration of about 12.8% and an acid concentration of about 1.09%.
46/2, designated xe2x80x98Shanixe2x80x99, is characterized by reddish-orange fruit having few seeds and flowers with anthers bearing viable pollen. Table 1 shows some of the characteristics of the new tree compared to the seed parent xe2x80x98Wilkingxe2x80x99 and pollen parent xe2x80x98Michalxe2x80x99. All observations were made in Israel on citrus 5-6 years old. Color designations have been determined from The RHS Colour Chart published by the Royal Horticultural Society, London.
Although xe2x80x98Meravxe2x80x99 (U.S. Plant patent application Ser. No. 09/716,984) and xe2x80x98Shanixe2x80x99 are sibling cultivars, they can be easily distinguished from each other as shown in Table 2.
The following is a detailed description of the new mandarin citrus variety based on observations made under typical Israeli grove conditions.
The leaf shape, tree size and shape of xe2x80x98Shanixe2x80x99 are intermediate between the seed parent xe2x80x98Wilkingxe2x80x99 and the pollen parent xe2x80x98Michalxe2x80x99. Young shoots have no anthocyanin coloration at the tip. The tree is quite productive with a slight tendency to alternate bearing (lower yield of fruit after a year of heavy bearing if fruit is not harvested). The canopy is moderately dense. The bark of the young shoots is initially smooth and green, gradually turning into a smooth brown-gray.
The chromosome number of the tree is diploid (2n=18) as is the chromosome number of the two parents.
The leaves somewhat resemble xe2x80x98Michalxe2x80x99 in size and shape. The leaf shape in cross section is slightly concave. Foliar flushes, as measured in Bet Dagan, Israel, occur between April and September. The firmness of the leave blade is relatively weak, without undulation. Petioles are without wings or have very narrow wings.
The characteristics of the flowering and the flower parts are similar to xe2x80x98Michalxe2x80x99. The flower has almost the same size as the flower of xe2x80x98Michalxe2x80x99. All flowers of mandarin cultivars are very much alike in color of petal (both sides are white), anthers, pistils, etc. Flowering as measured in Bet Dagan, Israel, occurs between mid March and the beginning of April. Terminal flower buds have no anthocyanin coloration. Anther color is yellow with 88% stainable pollen grain as obtained by staining with acetocarmine..
The fruit has few seeds, about 0 to 9 seeds per fruit. The fruit shape is oblate and medium in size. When 50 fruits were measured, the fruit had an average weight of 112 grams, an average height of 49 mm, and an average diameter of 65 mm. The fruit surface is usually smooth with a reddish-orange color, 34A, on The Royal Horticultural Society of London Colour Chart. Fruit ripening does not differ from outside of the canopy to the inside, but the fruit color of the outside canopy is a little brighter compared to the fruit color of the inside canopy. There is no persistence of the style and the areola is not completely developed. A small navel is usually present, similar to pollen parent xe2x80x98Michalxe2x80x99. The rind is thin and relatively easy to peel.
The color of the albedo is reddish and the flesh is dark orange in color. The fruit contains 10-12 segments and is very juicy. The external color of the seed is white and the internal color is greyed-orange. The color of the cotyledons is greyed-green. The seed size, shape and texture are quite similar to that of xe2x80x98Michalxe2x80x99. The seed size is medium. The fruit reaches maturity in February in Israel. The ripening of the fruit on the tree and within the fruit is uniform. Fruit remaining on the tree does not re-green and does begin to lose quality until March. The fruit has an attractive appearance and an excellent flavor and aroma.